The Federal Aviation Administration has temporarily suspended the registration of small drones during overnight hours, citing reports of site performance issues it received from a few users.

The move by the agency comes as completed registrations have soared to over 45,000 since it started offering the facility from Monday afternoon.

The maintenance is being done ahead of an expected surge in demand on Christmas Day. The FAA cited industry estimates that forecast that as many as 400,000 small drones, also known as small Unmanned Aircraft Systems, could be sold during the holidays.

The agency said the registration site would be taken offline on Tuesday night and on Wednesday night at 9.00 p.m. Eastern time. "We expect to resume service around 6 a.m on Wednesday and Thursday," it said in a statement late Tuesday.

The FAA introduced the mandatory registration of consumer drones ahead of the holiday season in view of concerns about the illegal use of the drones. There have been reports of sightings of drones flying close to other aircraft, and also of drones interfering during emergency measures such as the recent firefighting in San Bernardino County, California.

Under the rules, all small UAS that weigh more than 0.55 pounds (250 grams) and less than 55 pounds (about 25 kilograms) must be registered. Payloads such as on-board cameras have to be included to arrive at the weight.

After registration, the applicant will receive a certificate and a unique identification number for the UAS owner, which must be marked on the aircraft. Current rules limit the small drones to flying below 400 feet altitude, within line of sight at all times, and away from airports, stadiums or sporting events, emergency services and manned aircraft.

The FAA said that customers will be able to use the registration system throughout the day on Wednesday before it is taken offline again in the evening.

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